Add Mux, transport binding and ctrl msg handling layers of MCTP capsu…

…le (#36)

This PR adds the basic structure for the Mux MCTP driver layer, the transport binding layer, and the handling of MCTP control messages.
At this stage, the code remains untested, and the modules have yet to be instantiated.
The implementation includes the Set EID and Get EID commands, with plan to add other mandatory managed MCTP device commands once the basic commands have been tested and validated.

Cargo.toml

@@ -17,6 +17,7 @@ members = [
     "registers/systemrdl",
     "rom",
     "runtime",
+    "runtime/capsules",
     "runtime/apps/pldm",
     "runtime/i3c",
     "tests/hello",
@@ -63,6 +64,7 @@ gdbstub_arch = "0.2.4"
 getrandom = "0.2"
 hex = "0.4.3"
 i3c-driver = { path = "runtime/i3c" }
+capsules-runtime = { path = "runtime/capsules" }
 lazy_static = "1.4.0"
 num-derive = "0.4.2"
 num_enum = "0.7.2"

docs/src/mctp.md

@@ -303,7 +303,7 @@ pub struct VirtualMCTPDriver {
 pub trait MCTPSender {
     /// Sets the client for the `MCTPSender` instance.
     /// In this case it is MCTPTxState which is instantiated at the time of
-    fn set_client(&self, client: &dyn MCTPSendClient);
+    fn set_client(&self, client: &dyn MCTPTxClient);
 
     /// Sends the message to the MCTP kernel stack.
     fn send_msg(&self, dest_eid: u8, msg_tag: u8, msg_payload: SubSliceMut<'static, u8>);
@@ -313,15 +313,15 @@ pub trait MCTPSender {
 /// message is sent.
 /// The 'send_done' function in this trait is invoked after the MCTPSender
 /// has completed sending the requested message.
-pub trait MCTPSendClient {
+pub trait MCTPTxClient {
     fn send_done(&self, msg_tag: Option<u8>, result: Result<(), ErrorCode>, msg_payload: SubSliceMut<'static, u8> )
 }
 
 pub struct MCTPTxState<M:MCTPTransportBinding> {
     /// MCTP Mux driver reference
     mctp_mux_sender: &MuxMCTPDriver<M>,
     /// Client to invoke when send done. This is set to the corresponding VirtualMCTPDriver instance.
-    client: OptionalCell<&dyn MCTPSendClient>,
+    client: OptionalCell<&dyn MCTPTxClient>,
     /// next MCTPTxState node in the list
     next: ListLink<MCTPTxState<M: MCTPTransportBinding>>,
     /// The message buffer is set by the virtual MCTP driver when it issues the Tx request.
@@ -335,7 +335,7 @@ pub struct MCTPTxState<M:MCTPTransportBinding> {
 /// This is the trait implemented by VirtualMCTPDriver instance to get notified of
 /// the messages received on corresponding message_type.
 pub trait MCTPRxClient {
-    fn receive(&self, dst_eid: u8, msg_type: u8, msg_Tag: u8, msg_payload: &[u8]);
+    fn receive(&self, dst_eid: u8, msg_type: u8, msg_tag: u8, msg_payload: &[u8]);
 }
 
 /// Receive state

runtime/Cargo.toml

@@ -20,3 +20,4 @@ riscv = { git = "https://github.com/tock/tock.git", rev = "b128ae817b86706c8c4e3
 riscv-csr = { git = "https://github.com/tock/tock.git", rev = "b128ae817b86706c8c4e39d27fae5c54b98659f1" }
 rv32i = { git = "https://github.com/tock/tock.git", rev = "b128ae817b86706c8c4e39d27fae5c54b98659f1" }
 tock-registers.workspace = true
+capsules-runtime.workspace = true

runtime/capsules/Cargo.toml

@@ -0,0 +1,15 @@
+# Licensed under the Apache-2.0 license
+
+[package]
+name = "capsules-runtime"
+version.workspace = true
+authors.workspace = true
+edition.workspace = true
+
+[dependencies]
+kernel = { git = "https://github.com/tock/tock.git", rev = "b128ae817b86706c8c4e39d27fae5c54b98659f1" }
+
+capsules-extra = { git = "https://github.com/tock/tock.git", rev = "b128ae817b86706c8c4e39d27fae5c54b98659f1" }
+i3c-driver.workspace = true
+zerocopy.workspace = true
+bitfield.workspace = true

runtime/capsules/src/lib.rs

@@ -0,0 +1,6 @@
+// Licensed under the Apache-2.0 license
+
+#![cfg_attr(target_arch = "riscv32", no_std)]
+#![forbid(unsafe_code)]
+
+pub mod mctp;

runtime/capsules/src/mctp/base_protocol.rs

@@ -0,0 +1,103 @@
+// Licensed under the Apache-2.0 license
+
+//! This file contains the types, structs and methods associated with the
+//! MCTP Transport header, including getter and setter methods and encode/decode
+//! functionality necessary for transmission.
+//!
+
+use bitfield::bitfield;
+use zerocopy::{FromBytes, Immutable, IntoBytes};
+
+pub const MCTP_HDR_SIZE: usize = 4;
+
+bitfield! {
+    #[repr(C)]
+    #[derive(Clone, FromBytes, IntoBytes, Immutable)]
+    pub struct MCTPHeader([u8]);
+    impl Debug;
+    u8;
+    rsvd, _: 4, 0;
+    pub hdr_version, set_hdr_version: 7, 4;
+    pub dest_eid, set_dest_eid: 15, 8;
+    pub src_eid, set_src_eid: 23, 16;
+    pub som, set_som: 24, 24;
+    pub eom, set_eom: 25, 25;
+    pub pkt_seq, set_pkt_seq: 27, 26;
+    pub tag_owner, set_tag_owner: 28, 28;
+    pub msg_tag, set_msg_tag: 31, 29;
+}
+
+impl Default for MCTPHeader<[u8; MCTP_HDR_SIZE]> {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl MCTPHeader<[u8; MCTP_HDR_SIZE]> {
+    pub fn new() -> Self {
+        MCTPHeader([0; MCTP_HDR_SIZE])
+    }
+
+    #[allow(clippy::too_many_arguments)]
+    pub fn prepare_header(
+        &mut self,
+        dest_eid: u8,
+        src_eid: u8,
+        som: u8,
+        eom: u8,
+        pkt_seq: u8,
+        tag_owner: u8,
+        msg_tag: u8,
+    ) {
+        self.set_hdr_version(1);
+        self.set_dest_eid(dest_eid);
+        self.set_src_eid(src_eid);
+        self.set_som(som);
+        self.set_eom(eom);
+        self.set_pkt_seq(pkt_seq);
+        self.set_tag_owner(tag_owner);
+        self.set_msg_tag(msg_tag);
+    }
+}
+
+#[derive(Debug, PartialEq)]
+pub enum MessageType {
+    MCTPControl,
+    PLDM,
+    SPDM,
+    SSPDM,
+    VendorDefinedPCI,
+    Invalid,
+}
+
+impl From<u8> for MessageType {
+    fn from(val: u8) -> MessageType {
+        match val {
+            0 => MessageType::MCTPControl,
+            1 => MessageType::PLDM,
+            5 => MessageType::SPDM,
+            6 => MessageType::SSPDM,
+            0x7E => MessageType::VendorDefinedPCI,
+            _ => MessageType::Invalid,
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_mctp_header() {
+        let mut header = MCTPHeader::new();
+        header.prepare_header(0x10, 0x08, 1, 1, 0, 0, 0);
+        assert_eq!(header.hdr_version(), 1);
+        assert_eq!(header.dest_eid(), 0x10);
+        assert_eq!(header.src_eid(), 0x08);
+        assert_eq!(header.som(), 1);
+        assert_eq!(header.eom(), 1);
+        assert_eq!(header.pkt_seq(), 0);
+        assert_eq!(header.tag_owner(), 0);
+        assert_eq!(header.msg_tag(), 0);
+    }
+}